.beta.-D-1-(6-amino-9H-purin-9-yl)-1-deoxyribofuranuronic acid esters (German Offenlegungsschrift No. 2,244,215), .beta.-D-1-(6-amino-9H-purin-9-yl)-1-deoxyribofuranuronamides (German Offenlegungsschrift No. 2,034,785) and .beta.-D-1-(6-amino-9H-purin-9-yl)-1-deoxyribofuranose derivatives nitrated on the ribose radical (German Offenlegungsschrift No. 2,105,560) have an advantageous cardiac action.